Removed useless code, two GFK to one model don't work anyways…
Prepare 0.11
Revert "Removed useless code, two GFK to one model don't work anyways…"

This reverts commit 188182b97db6682ef0624404ba4ff0f74270dbdd.
Release 0.11.1
Updated travis.yml
Increased version to 0.12a1
Remove pointless import
Remove duplicate code
Proper (hopefully) fix for https://github.com/alex/django-taggit/commit/20a8063c4deb8fb3c5440787cd8114cb2fdf8537#commitcomment-4715554